how to change angle

So I have not used the Ellsworth jig. So I started reading.
Turns out it is basically the same as a Wolverine vari grind.
And the instructions state that it will work with any system, but also shows you how to make your own.
Did you make a sliding arm for your jig?
Do you have the instruction sheet?
If not you can get it here, Document tab
https://www.woodturnerscatalog.com/p/94/1562/ellsworth-Grinding-Jig
or here too,
https://mendocinowoodturnersguild.org/wp-content/uploads/TheEllsworth-SharpeningJig.pdf

So I did not find any instructions specifically for an exact measurement to change the grind angle from 65 to 55.
But there is some interesting reading here about bowl gouge angles.
https://turnawoodbowl.com/bowl-gouge-sharpening-angles-illustrated-guide/

Now I am using the Wolverine system, and can not give you a perfect number for what you have.
But I also use raptor jigs that give me a repeatable angle every time. (I just can't eye ball it anymore, my old eyes never get it right).
So I went out just now and took a look. The raptor jigs come in 60. and 50, 45, 40 , and 35 degree.
Setting up my grinder at 60, and then at 50 degree, shortened the arm by 5/16".
So to my surprise, I decided to go to 40 degree and measure. that took another 7/16" off the 50.
So there is no magic number to take 10 degree steps. But if you just go a few 16ths at a time you will get there. just make sure you keep a diary.

Good luck.

The 'stick out' is 2". David Ellsworth grinds his gouges to 60 degrees, using his jig in conjunction with one of Don Gieger's solutions on a Wolverine system. Here's a link to a video where Don shows the setup (using a Varigrind jig).

Also, the jig you showed in your original post looks like one of Eddie Castelin's "Blackhawk" jigs. If so, it is not an Ellsworth jig … the angle of the leg is significantly different … and likely won't produce the desired results.